RUI: CAS: Novel Carbon Nanosphere Encapsulated Bimetallic Catalysts and Metal-CeO2 Interfaces for CO2 Conversion to Value-added Chemicals

在化学系化学催化项目的支持下，长岛大学(Post)的张成(音译)正在开发将二氧化碳转化为有用产品的新型催化剂。作为一种温室气体，二氧化碳水平升高可能会引发重大的环境问题。迫切需要减少二氧化碳排放，以减轻温室气体水平上升对我们星球的负面影响。因此，高效地捕获和利用二氧化碳以生产增值化学品是非常可取的。这项研究旨在通过催化加氢将二氧化碳转化为有价值的聚合物和塑料的构建块，目前这些聚合物和塑料主要来自化石碳源。该项目的一个关键意义是确定可用于设计有效的二氧化碳转化催化剂的趋势和主导因素。这项工作的新发现可能使对所研究系统的催化剂性能进行可调控制，并促进发现用于二氧化碳转化的新催化剂。张博士将把本科生研究和教育作为这个由NSF资助的项目的重要组成部分。张博士的实验室里有来自不同种族和专业的学生。让本科生参与研究是他们教育的一个关键因素，这不仅是为了磨练他们的量化和批判性思维能力，也是为了建立他们对科学研究如何进行的实际欣赏和理解。通过他们在这个科学项目上的工作，学生们将体验到承担责任、解决问题、坚持不懈、彻底、团队合作、承诺和耐心的重要元素，这些都是研究科学家的有用品质。在这个项目下，长岛大学的张成团队致力于了解在碳纳米球(CNS)的限制下，被包裹的过渡金属和金属氧化物催化的二氧化碳加氢制低碳烯烃的反应机理和主要影响因素。我们的目标是能够使用这些参数来调整催化剂的功能，以实现高效的二氧化碳转化。具体地说，张团队将探索金属和/或金属碳化物颗粒大小、金属合金形成、金属-金属氧化物相互作用和限制效应对二氧化碳转化为增值化学品的催化剂活性、选择性和稳定性的影响。催化性能将从结构表征和密度泛函理论(DFT)计算的角度进行考察，以获得更多的见解。这些研究的特别目标是(I)利用CNS的限制来保护Fe-M纳米颗粒不会团聚并保持其还原状态，(Ii)利用CeO2上丰富的氧空位，(Iii)利用CNS的疏水性和石墨性，以及(Iv)利用CNS孔内的短扩散长度来最大限度地减少不希望发生的烯烃二次反应。综合、评估、高级表征和DFT计算的整合对这项科学的成功至关重要，并突显了这项研究的多面性。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Chemical Catalysis program in the Division of Chemistry, Cheng Zhang of Long Island University (Post) is developing new catalysts for CO2 conversion to useful products. As a greenhouse gas, CO2 at elevated levels can give rise to significant environmental issues. There is an urgent need to mitigate CO2 emissions to alleviate the negative impact of elevated greenhouse gas levels on our planet. As such, efficient capture and utilization of CO2 to produce value-added chemicals is highly desirable. This research aims to convert CO2 by catalytic hydrogenation to valuable building blocks for polymers and plastics that are currently produced primarily from fossil carbon sources. A key significance of this project is to identify trends and dominant factors that can be utilized to design efficient catalysts for CO2 conversion. New discoveries from this work may enable the tunable control of catalyst properties for the systems under study, and facilitate the discovery of new catalysts for CO2 conversion. Dr. Zhang will incorporate undergraduate research and education as a significant component of this NSF-funded project. Dr. Zhang’s lab includes students of various ethnicity and majors. Involving undergraduates in research is a crucial element of their education, not only to hone their quantitative and critical thinking skills but also to build their practical appreciation and understanding of how scientific research is conducted. Through their work on this scientific project, students will experience important elements of taking responsibility, problem-solving, persistence, thoroughness, teamwork, commitment and patience, all useful traits for the research scientist. Under this project, the group of Cheng Zhang at Long Island University is working to understand the reaction mechanism and dominant factors affecting CO2 hydrogenation to light olefins as catalyzed by encapsulated transition metals and metal oxides within the confines of carbon nanospheres (CNS). The goal is to be able to use these parameters to tune catalyst functionality for efficient CO2 conversion. Specifically, the Zhang team will probe the effects of metal and/or metal carbide particle size, metal alloy formation, metal-metal oxide interaction and confinement effects on the catalyst activity, selectivity, and stability for CO2 conversion to value-added chemicals. Catalytic performance will be examined in light of structural characterization and in view of density functional theory (DFT) calculations to gain more insight. Particular goals of these investigations are (i) to take advantage of the confinement of the CNS to protect Fe-M nanoparticles from agglomeration and retain their reduced state, (ii) to exploit the abundant oxygen vacancies on CeO2, (iii) to take advantage of the hydrophobic and graphitic nature of CNS with defect sites, and (iv) to use the short diffusion length inside the CNS pores to minimize undesired olefin secondary reactions. The integration of synthesis, evaluation, advanced characterization, and DFT calculations is critical for the success of this science and highlights the multi-faceted nature of the study.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.